1. Technical Field
The present invention generally relates to an anchoring device and/or suture and methods for its use. More particularly, the present invention relates to a coated anchoring device and/or suture and methods for its use.
2. Background Art and Technical Problems
In many surgical procedures requiring tissue to tissue, tissue to bone, and bone to bone fixation, anchoring devices are used in conjunction with a suture to secure the fixation site. For example, the anchoring device could be a screw to join tissue and/or bone, and the suture could be a type of stitch to bind the tissue and/or bone. The anchoring device and/or suture are susceptible to bacteria at every stage of insertion, from external to the body to internal to the tissue and/or bone. Although sterile conditions are desired at each stage of insertion, in practice, that is not always possible. For example, bacteria may originate outside the body and then use the anchoring device and/or suture as a vehicle for invading the body. Alternatively, bacteria may already exist inside the body and the anchoring device and/or suture may carry such bacteria to other areas continuing the infection process.
Sutures are available as both monofilaments and braided filaments with the filaments being comprised of a variety of polymers. The most common suture is a braided polyester. Wicking of bacteria in the suture can be a concern. Braided filaments possess interstices which are sites where bacteria can proliferate. As these bacterial colonies outgrow their homes, they begin to migrate further into the suture causing wicking. Thus, wicking is the process of bacteria infecting the suture and/or surrounding areas.
Sutures may be comprised of a variety of materials including, but not limited to, cellulose (cotton), protein-cellulose (silk), processed collagen (catgut), nylon, polypropylene, Aramid, polyglycolic acid, polyesters, polytetraflourethylene, steel, copper, silver, aluminum, various alloys, Mersilene(trademark), Ticron(trademark), Ethilon(trademark), Prolene(trademark), Ethiflex(trademark), Polyglactin 910(trademark), polyglycolide-lactide polymer (e.g., Vicryl(trademark)), polydioxanone (e.g., PDSm(trademark)), polyglecaprone 25 (e.g., Monocryl(trademark)), polyglyconate (e.g., Maxon(trademark)), and Ethibond(trademark).
In other areas of medicine, known methods for reducing the potential for site infection include coatings on catheters or external fixation pins. One common anti-microbial used in these applications is metallic silver. For example, catheters coated with silver have already shown a reduction in infections of the urinary tract where they are used. In addition, antibiotic-impregnated cement has been used for postoperative infections. Fish et al., 49 Amer Jour Hosp Pharm 2469 (October 1992). For implant infections, an antibiotic-impregnated silicone rubber coating has been used to cover the implant devices. Rushton et al., 52 Jour of Neurology, Neurosurgery, and Psychiatry 223 (1989). Also, recombinant human Transforming Growth Factor-B1 adsorbed onto ceramic implants has been shown to improve bone cell repair. Overgaard et al., 43rd Annual Meeting of the Orthopedic Research Society (San Francisco, Calif., Feb. 9-13, 1997).
However, prior art devices and methods for reducing infection and expediting healing have mainly been directed to implants alone. Such devices and methods have failed to address other key elements introduced into the body during surgery, such as sutures and the problems associated with those elements, such as wicking. Accordingly, a method and apparatus which substantially reduce infection, expedite the healing process, and reduce the problems associated with wicking are needed.
The present invention includes a coated/impregnated anchoring device and/or suture which prevents infection, delivers site specific drugs, promotes tissue regeneration, and/or promotes bone regeneration in a variety of medical procedures. Coatings for the coated anchoring device and/or suture may include anti-microbial agents for fighting infection, site specific drugs for delivering drugs, or human growth factors for delivering growth factors. Thus, the present invention substantially reduces infection, expedites the healing process, and provides easier drug delivery.